The present invention is deemed to be a considerable and meritorious improvement over the inventions disclosed in U.S. Pat. Nos. 4,022,479, 4,114,902 and 4,466,620.
In many industries, it is extremely important to obtain a seal for rotating shafts emerging from a bearing and its housing which prevents the lubricants associated with the bearings from leaking externally of the associated housing or bearing support and for preventing contaminants in the environment from working themselves through the seal and into the lubricant for the bearings.
U.S. Pat. No. 4,022,479 incorporates a disclosure wherein there is taught a sealing ring structure which has an object elimination of the loss of lubricant from the bearings supporting a rotating shaft. The sealing ring structure as disclosed also eliminates the movement of contaminants into the bearing area and lubricant within the housing. It was therein disclosed a sealing structure that is composed of two rings, preferably metal, one of which is fixed to the housing and the other is fixed to rotate with the shaft. The ring that is fixed to the housing has a labyrinth-type of seal next to the shaft which prevents lubricant from moving outside of the housing along the shaft.
In U.S. Pat. No. 4,022,479, a joint was provided between the two rings which is composed of an annular recess in the first ring axially outwardly of the housing and an annular flange on the second ring that fits within the aforementioned annular recess of the first ring. The construction of the annular recess and the annular flange are complimentary, so that when the two rings are rotating relative to one another, they will not tend to bind, or create a heated frictional disposition between them. There was also provided in the first sealing ring an elongated circular passage that communicates from the aforementioned annular recess. In the embodiment taught in this prior patent, the annular flange of the second sealing ring has axial notches cut therein. With such an arrangement, foreign particles that migrate into the joint formed by the recess and flange are propelled, and directed, back into the environment. It will be noted that the first ring is fixed to the housing and the second ring is adapted to rotate with the shaft by suitable frictional sealing means. However, there is no rubbing, wear or contact between the respective sealing rings.
The invention of U.S. Pat. No. 4,114,902 was an ingenious improvement over the device disclosed in U.S. Pat. No. 4,022,479. The improvement included the use of at least one groove on the periphery of the annular flange of the second ring member. Additionally, the outer axial wall of the accomodating recess in the first ring member also contained at least one groove. It was noted in U.S. Pat. No. 4,114,902 that these grooves act to inhibit particle migration, regardless of relative peripheral speed of the rotating rings and to provide a circumferential path for the gravitational exclusion of foreign material even in the event of zero relative rotation.
The invention of U.S. Pat. No. 4,466,620 is a further ingenious improvement over the devices disclosed in the aforementioned patents and solves additional problems. The improvement, among other items, includes a modification of the hole in the first sealing ring. The hole was modified such that its axially extending length is greater than its circumferentially extending width. This improvement eliminated expulsion problems which occasionally arose due to the relative axial displacement of the sealing rings and provided an effective vent to expell foreign matter from the annular recess, or recesses if more than one flange-recess combination were required.
U.S. Pat. No. 4,466,620 also encompassed an additional improvement wherein a portion of the first ring member that faces the bearing located inside the housing is axially extended to form a shielding protrusion. This improvement wards off the profuse quantities of liquid lubricant that are continuously directed at the first ring member in certain situations, e.g. multiple gear and pinion speed reduction gearing.
Although the above advances have solved a great number of problems, problems were still encountered in various particular work applications. Accordingly, it would be highly desirable to have a sealing ring structure that eliminates those problems.